<?php
/**
 * Class for a set of entries for translation and their associated headers
 *
 * @version $Id: translations.php 718 2012-10-31 00:32:02Z nbachiyski $
 * @package pomo
 * @subpackage translations
 */

require_once dirname(__FILE__) . '/entry.php';

if (!class_exists('Translations')):
    class Translations
    {
        var $entries = array();
        var $headers = array();

        /**
         * Add entry to the PO structure
         *
         * @param object &$entry
         * @return bool true on success, false if the entry doesn't have a key
         */
        function add_entry($entry)
        {
            if (is_array($entry)) {
                $entry = new Translation_Entry($entry);
            }
            $key = $entry->key();
            if (false === $key) return false;
            $this->entries[$key] = & $entry;
            return true;
        }

        function add_entry_or_merge($entry)
        {
            if (is_array($entry)) {
                $entry = new Translation_Entry($entry);
            }
            $key = $entry->key();
            if (false === $key) return false;
            if (isset($this->entries[$key]))
                $this->entries[$key]->merge_with($entry);
            else
                $this->entries[$key] = & $entry;
            return true;
        }

        /**
         * Sets $header PO header to $value
         *
         * If the header already exists, it will be overwritten
         *
         * TODO: this should be out of this class, it is gettext specific
         *
         * @param string $header header name, without trailing :
         * @param string $value header value, without trailing \n
         */
        function set_header($header, $value)
        {
            $this->headers[$header] = $value;
        }

        function set_headers($headers)
        {
            foreach ($headers as $header => $value) {
                $this->set_header($header, $value);
            }
        }

        function get_header($header)
        {
            return isset($this->headers[$header]) ? $this->headers[$header] : false;
        }

        function translate_entry(&$entry)
        {
            $key = $entry->key();
            return isset($this->entries[$key]) ? $this->entries[$key] : false;
        }

        function translate($singular, $context = null)
        {
            $entry = new Translation_Entry(array('singular' => $singular, 'context' => $context));
            $translated = $this->translate_entry($entry);
            return ($translated && !empty($translated->translations)) ? $translated->translations[0] : $singular;
        }

        /**
         * Given the number of items, returns the 0-based index of the plural form to use
         *
         * Here, in the base Translations class, the common logic for English is implemented:
         *    0 if there is one element, 1 otherwise
         *
         * This function should be overrided by the sub-classes. For example MO/PO can derive the logic
         * from their headers.
         *
         * @param integer $count number of items
         */
        function select_plural_form($count)
        {
            return 1 == $count ? 0 : 1;
        }

        function get_plural_forms_count()
        {
            return 2;
        }

        function translate_plural($singular, $plural, $count, $context = null)
        {
            $entry = new Translation_Entry(array('singular' => $singular, 'plural' => $plural, 'context' => $context));
            $translated = $this->translate_entry($entry);
            $index = $this->select_plural_form($count);
            $total_plural_forms = $this->get_plural_forms_count();
            if ($translated && 0 <= $index && $index < $total_plural_forms &&
                is_array($translated->translations) &&
                isset($translated->translations[$index])
            )
                return $translated->translations[$index];
            else
                return 1 == $count ? $singular : $plural;
        }

        /**
         * Merge $other in the current object.
         *
         * @param Object &$other Another Translation object, whose translations will be merged in this one
         * @return void
         **/
        function merge_with(&$other)
        {
            foreach ($other->entries as $entry) {
                $this->entries[$entry->key()] = $entry;
            }
        }

        function merge_originals_with(&$other)
        {
            foreach ($other->entries as $entry) {
                if (!isset($this->entries[$entry->key()]))
                    $this->entries[$entry->key()] = $entry;
                else
                    $this->entries[$entry->key()]->merge_with($entry);
            }
        }
    }

    class Gettext_Translations extends Translations
    {
        /**
         * The gettext implementation of select_plural_form.
         *
         * It lives in this class, because there are more than one descendand, which will use it and
         * they can't share it effectively.
         *
         */
        function gettext_select_plural_form($count)
        {
            if (!isset($this->_gettext_select_plural_form) || is_null($this->_gettext_select_plural_form)) {
                list($nplurals, $expression) = $this->nplurals_and_expression_from_header($this->get_header('Plural-Forms'));
                $this->_nplurals = $nplurals;
                $this->_gettext_select_plural_form = $this->make_plural_form_function($nplurals, $expression);
            }
            return call_user_func($this->_gettext_select_plural_form, $count);
        }

        function nplurals_and_expression_from_header($header)
        {
            if (preg_match('/^\s*nplurals\s*=\s*(\d+)\s*;\s+plural\s*=\s*(.+)$/', $header, $matches)) {
                $nplurals = (int)$matches[1];
                $expression = trim($this->parenthesize_plural_exression($matches[2]));
                return array($nplurals, $expression);
            } else {
                return array(2, 'n != 1');
            }
        }

        /**
         * Makes a function, which will return the right translation index, according to the
         * plural forms header
         */
        function make_plural_form_function($nplurals, $expression)
        {
            $expression = str_replace('n', '$n', $expression);
            $func_body = "
			\$index = (int)($expression);
			return (\$index < $nplurals)? \$index : $nplurals - 1;";
            return create_function('$n', $func_body);
        }

        /**
         * Adds parantheses to the inner parts of ternary operators in
         * plural expressions, because PHP evaluates ternary oerators from left to right
         *
         * @param string $expression the expression without parentheses
         * @return string the expression with parentheses added
         */
        function parenthesize_plural_exression($expression)
        {
            $expression .= ';';
            $res = '';
            $depth = 0;
            for ($i = 0; $i < strlen($expression); ++$i) {
                $char = $expression[$i];
                switch ($char) {
                    case '?':
                        $res .= ' ? (';
                        $depth++;
                        break;
                    case ':':
                        $res .= ') : (';
                        break;
                    case ';':
                        $res .= str_repeat(')', $depth) . ';';
                        $depth = 0;
                        break;
                    default:
                        $res .= $char;
                }
            }
            return rtrim($res, ';');
        }

        function make_headers($translation)
        {
            $headers = array();
            // sometimes \ns are used instead of real new lines
            $translation = str_replace('\n', "\n", $translation);
            $lines = explode("\n", $translation);
            foreach ($lines as $line) {
                $parts = explode(':', $line, 2);
                if (!isset($parts[1])) continue;
                $headers[trim($parts[0])] = trim($parts[1]);
            }
            return $headers;
        }

        function set_header($header, $value)
        {
            parent::set_header($header, $value);
            if ('Plural-Forms' == $header) {
                list($nplurals, $expression) = $this->nplurals_and_expression_from_header($this->get_header('Plural-Forms'));
                $this->_nplurals = $nplurals;
                $this->_gettext_select_plural_form = $this->make_plural_form_function($nplurals, $expression);
            }
        }
    }
endif;

if (!class_exists('NOOP_Translations')):
    /**
     * Provides the same interface as Translations, but doesn't do anything
     */
    class NOOP_Translations
    {
        var $entries = array();
        var $headers = array();

        function add_entry($entry)
        {
            return true;
        }

        function set_header($header, $value)
        {
        }

        function set_headers($headers)
        {
        }

        function get_header($header)
        {
            return false;
        }

        function translate_entry(&$entry)
        {
            return false;
        }

        function translate($singular, $context = null)
        {
            return $singular;
        }

        function select_plural_form($count)
        {
            return 1 == $count ? 0 : 1;
        }

        function get_plural_forms_count()
        {
            return 2;
        }

        function translate_plural($singular, $plural, $count, $context = null)
        {
            return 1 == $count ? $singular : $plural;
        }

        function merge_with(&$other)
        {
        }
    }
endif;
